Jellyfish stings

Jellyfish and bluebottles have thousands of tiny stinging cells (nematocysts) on their tentacles. When something (or someone) touches them, the cells shoot out tiny harpoons filled with venom into the skin. This is painful and causes a stinging reaction.  

The stings can cause sudden intense pain, with burning and itching at the site of the sting. The sting often appears as raised red stripes on your skin (welts).  
 

For some people,  jellyfish stings can cause a rare but serious allergic reaction called anaphylaxis. It requires immediate treatment and urgent medical attention – call 111 and ask for an ambulance.

Symptoms of anaphylaxis include:

• swelling around the lips and eyes
• rapid development of a rash
• shortness of breath or wheezing
• chest tightness
• severe dizziness or fainting
• persistent sneezing or coughing
• a hoarse voice
• difficulty swallowing or throat tightness
• signs of shock, such as pale skin, rapid heartbeat and fainting.

Read more about anaphylaxis.

If you’ve been stung on the eye, mouth, throat or genitals, or you've have had a bad allergic reaction, get medical help right away. Otherwise, you can usually treat a sting at the beach and then at home. 

The bluebottle (see the image below) is the jellyfish most commonly involved in stings around Aotearoa New Zealand. However, treatment of stings is the same whatever jellyfish is involved.  

Image credit: Flickr

What to do

If you’ve been stung by a sea creature at the beach, ask for help from a lifeguard. If there’s no help available: 

• Rinse the affected area with sea water to remove the tentacles. Don’t use fresh water as this can make the stingers release more venom.
• If tentacles are still attached, use a dry towel or the edge of a credit card to gently remove them. Be careful not to get stingers on your hands – wear gloves if you can.
• Soak the stung area in very warm tap water (as hot as you can bear but no more than 45°C) for 15 to 20 minutes. You can do this using a towel or face cloth rinsed under very warm tap water or have a shower to get the water onto a sting on your torso/trunk/stomach or back. You can repeat this until 2 hours after you’ve been stung. If it’s painful, you can try taking paracetamol.
• Antihistamine tablets or creams might help relieve itching and swelling.  
• If the pain and irritation doesn’t go away, talk to your healthcare provider, a pharmacist or call Healthine on 0800 611 116.

What not to do

• Don’t urinate (pee) on the sting – this can make it feel worse.
• Don’t put an ice pack on the sting.
• Don’t put vinegar or methylated spirits on the sting – these can make the sting hurt more.
• Don’t touch any tentacles with your bare hands.
• Don’t cover or wrap the wounded area.  

Video: How to treat a jellyfish sting

(WebMD, US, 2016)

If you get an itchy red rash a few minutes or even hours after you’ve been swimming in the ocean, it may be from ‘sea lice bites’ which are actually stings from the larvae of jellyfish and some sea anemones.   
 
The rash, called sea bather’s eruption, is a form of dermatitis, usually caused by tiny jellyfish larvae and sea anemone in the water that get trapped between your skin and your swimwear/ togs. Sea lice bites cause itchy red dots or bumps that can look like flea bites.  

You’re more likely to be bitten or stung by these tiny sea critters during summer, as warm or sub-tropical waters create good conditions for them to grow. 

 
As with jellyfish stings, don’t use fresh water to rinse the area because it can make the sting or rash worse.  

• Take off your bathing suit or togs as soon as possible and rinse your body in salt water.
• Gently pat your skin dry.
• Try not to scratch! Ask your pharmacist for advice about creams to numb the area to help with the itchiness. You can also use an antihistamine cream or tablet.
• If the area is painful, try taking paracetamol.
• If your rash is severe, see your healthcare provider. 

• Avoid shallow water, playing at the water’s edge and exploring rock pools as this is where the jellyfish and anemone larvae or ‘sea lice’ are more likely to be found.
• Rinse your body after swimming – preferably in salt water. If you know there are jellyfish or sea lice in your area, always rinse your swimwear after swimming as well. Then wash your swimwear in hot water and dry it thoroughly – preferably in the dryer.
• Consider wearing tighter swimwear or a bikini (instead of a 1-piece) while swimming so these sea creatures are less likely to get trapped between your swimwear and your skin.
• If you see jellyfish or bluebottles on the beach don’t touch them.